JPS60128928A - Reed valve for two-cycle engine - Google Patents

Abstract

PURPOSE:To prevent a valve reed from bouncing and reduce a cost, by making a valve body of synthetic resin, placing the valve reed in elastic contact with the valve body to close an opening at a crankcase chamber, and providing a curved surface of prescribed curvature radius, to surround the opening. CONSTITUTION:A reed valve body 11 is integrally molded from synthetic resin. Valve reeds 15 are placed in elastic contact with the valve body 11 to close the openings 13 of communication holes 14 provided in valve seat surfaces 12. A curved surface 16 is formed around each opening 13 so that the curved surface 16 extends from the valve seat surface 12 to the communication hole 14. The radius of the curvature of the curved surface 16, on the axial section of the valve body 11, is set at 0.5-5mm.. The curved surface 16 is molded at the same time as the valve body 11. When the valve reed 15 is closed after being opened, it is elastically deformed in contact with the curved surface 16 so that the valve reed is softly stopped. For that reason, the valve reed 15 does no bounce, so that its sealing property is improved. The disadvantage of a conventional reed valve body made of synthetic resin is thus eliminated to enhance the performance of an engine at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reed valve device for a two-stroke engine that controls opening and closing of an intake passage.

In a two-stroke engine, as is well known, fuel gas is sucked into the crank chamber by the negative pressure generated when the first piston rises, and the fuel gas sucked into the cylinder is filled by the pressure increase when the piston falls (scavenging). . This rounded intake passage communicates with the crank chamber, and is controlled by a valve that opens when the crank chamber has negative pressure and closes when there is positive pressure. As this control valve, a reed valve device that functions as a one-way valve is often used.

A reed valve device is a device in which a pulse reed is brought into elastic contact to block the intake port from the crank chamber side, and engine performance is greatly influenced by sealing performance, responsiveness, etc., so high functionality and durability are required. . Generally, a method is adopted in which a reed valve device is provided as a separate functional component and installed in the intake passage. Examples of this are shown in Figures 1 and 2.
As shown in the figure. Lead parboody l has upper and lower surfaces 2a, 2b
are formed so as to converge into a roof shape, and the upper and lower surfaces 2a,
1 [several openings 3 a * 3 bK arranged in 2b
Therefore, a through hole 4 penetrating back and forth is formed inside.

Pulble leads 5 are installed in the openings 3a and 3b so as to close the openings 3a and 3b.
A * 5 b is set. This reed valve 2day 1 is installed in the intake passage 7 leading to the crank chamber 6, with the Pulbree P5m, 5b facing the crank chamber 6 side. The vent hole 4 functions as an intake passage 7, and 1J controls opening and closing of the intake passage 7.
-)'l/? Lube device is configured.

The reed valve D1 is conventionally manufactured by aluminum casting, and the upper and lower surfaces 2a a 2b, that is, the valve seat surface, are precisely machined and then rubber is booted L.
7 to improve sealing performance and fire resistance, but this had the disadvantage of increasing manufacturing costs. Reed valve on the other hand? Day 1
There are products made of synthetic resin, which can be molded with high precision and require no post-processing, which has the advantage of reducing cost and weight.

However, the synthetic resin Zedei has the following problems.

This is due to the lack of elasticity of the shim coating, especially in high speed rotation ranges such as 7,000 to io, oo.

It is noticeable in the rpm range. That is, at high speed rotation, the pulse bleed opens and closes violently, and a phenomenon occurs in which the once-closed pulse bleed bounces back and reopens due to the impact when it closes. At this time, the pressure in the crank chamber begins to rise, so the pressure leaks into the intake passage, reducing scavenging efficiency and reducing engine output. It would be possible to coat the body with shims like aluminum, but it is difficult to coat synthetic resin with shims, and the advantage of using a synthetic resin body is halved in terms of cost.

In view of the above-mentioned problems, the purpose of this invention is to reduce the impact between the valve seat and the valve seat and prevent the valve seat from rebounding without any special processing. , the low-cost synthetic resin is made by Dee 2.
A cycle engine glue-P valve device is provided.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings showing embodiments of the present invention will be explained in detail below.

In FIGS. 3 and 4, the reed valve body 11 is integrally molded from synthetic resin, and the structure in which the valve reed 1 is elastically installed by closing the opening 13 of the through hole 14 provided in the valve seat surface 12 is the same as the conventional one. be. The periphery of the opening 13 is the fourth
As shown in the figure, from the valve seat surface to the through hole 14, curved surface 1
6 (hereinafter referred to as R-plane). 8th side 16 is o, s
'-5￥, radius is set, reed valve gi 1
It is molded simultaneously with the molding of 1.

With the above structure, the pulse bleed 15 opens in response to the negative pressure in the crank chamber to suck in fuel gas from the opening 13, and then the crank chamber is pressurized and the pulse bleed 15 closes. When it closes, the valve bleed 13 abuts against the valve seat surface 13 and is stopped, but since the abutment is only at the periphery, the central part is closed by the opening 13 due to inertia.
It is bent inward, and the peripheral edge of the opening 13 is formed into eight surfaces 16 as described above, and the area of the end face of the opening 13 is expanded, so the amount of bending is large, and the energy is absorbed accordingly, reducing the impact force. . Therefore, the possibility of the pulse bleed 15 jumping up is reduced. At the same time, the back surface of the pulse lead 15 maintains contact while sliding the contact line on the eight surfaces 16 according to the bending, so that the sealing performance is good. In this way, there is no pressure leakage from the crank chamber to the intake passage, improving intake efficiency and engine output.

Through the above two-stroke engine glue-P according to the present invention
The PALZO device is made of a plastic molded with a plastic ring mounted on the intake passage, and the opening that is opened and closed by the PULBRARY P is molded with an R surface of 0.5 to 5 radius on its periphery. When the valve P opens and then closes, it bends in contact with the R surface and is gently received, so there is no rebound, and it also makes line contact with the R surface, providing good sealing performance and satisfying its function as an opening/closing valve. In this way, the disadvantages of synthetic resin reed parbodies are eliminated, and the advantages of good productivity, light weight, and low cost are utilized to improve engine performance, especially output in the high-speed rotation range.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view showing one example of a reed valve device, Figure 2 is a longitudinal sectional view showing an example of a reed valve device;
The figures are an end view taken along arrow A in FIG. 1, FIG. 3 is an end view of essential parts showing an embodiment of the reed valve device according to the present invention, and FIG. 4 is an enlarged cross section taken along line B-B in FIG. 3. It is a diagram. DESCRIPTION OF SYMBOLS 11...Reed valve body, 12...Valve seat surface, 13...Opening, 14...Through hole, 15...Pulle bleed, 16.j.Curved surface (R surface). Figure 3 Figure 4 Figure 14 L

Claims (1)

[Claims] The valve body is configured to be installed in the intake passage leading to the crank chamber, has a through hole passing through it, closes the opening on the crank chamber side, and makes elastic contact with the valve bleed, and is molded with synthetic resin. A 2-cycle engine lubricating device characterized by having a curved surface with a radius of 0.5 to 5X around the periphery.